The present invention relates to an automatic packaging apparatus and, more particularly, to a device for binding packages with a band of tape made of thermoplastic material such as polypropylene.
Various devices for binding packages with packaging tape are known. The known devices have a work table on which an arc-shaped tape guide member is provided for forming a loop of tape by winding the tape through the guide member. The object to be bound is inserted through the loop of tape and the guide member and then the tape is tighten around the object. Devices of the above-mentioned type suffer from the drawback that the object is inserted through the guide member. This limits the size of packages that can be handled to the size of the guide member.
A partial solution is offeref by Japanese Patent publication No. 49 (1974)-4520 which describes a retractable arc-shaped guide member which is located on a work table. The packing tape is fed from below a base plate of the work table along and through the guide member. After the tape passes through the guide member, the leading end of the tape is clamped and the guide member is retracted. This leaves an initial loop of tape in place. Thereafter, more of the tape is paid out to enlarge the size of the loop to accommodate larger packages. After a package is inserted through the loop, the tape is tightened around the package and the ends of the tape are overlapped and joined and the excess cut off.
The above-mentioned retractable guide member still fails to provide the full desired functionality for a guide member. This is due in part to the positioning of the guide member at such a loctaion where it would not obstruct or interfere with the operation of an associated moving means which are provided for moving the tape.
Moreover, the guide member of the Japanese reference is designed to be temporarily retracted beneath the work table surface. It is therefore implemented from two, roughly symmetrical, guide pieces. This requries open spaces on each side of a guide fixing postion on the work table surface and the two pieces of the guide member had to be constructed with great mechanical precision to prevent tangling of the tape. In fact, the structure of the guide member of the above mentioned prior art is such that even its precise mechanical construction does not prevent the tape from falling out of the guide groove in the guide member or mfrom catching in the groove.
U.S. Pat. No. 4,378,626 describes a method and apparatus for forming a strap loop and securing it about an article. The strap is formed with the aid of a guide surface which, in one embodiment, is formed of a rotatable cam. After a primary small strap is formed with the aid of the cam, the strap is removed from the guide sursface, enlarged, and then tightened around an article.
U.S. Pat. Nos. 4,079,667 and 4,077,313 describe several embodiments for forming and tensioning a strap about an object including forming a primary strap loop by feeding a length of tape into a substantially circular cup-shaped guide. Once the primary loop is formed, th eguide is lowered and released from the primary loop and the size of the loop is expanded. In FIG. 10 of the above-mentioned U.S. Pat. No. 4,079,667 there is disclosed a disk-shaped guide member formed of two half disks and wherein a guide surface is defined in the guide member for forming the primary loop. To enlarge the loop the two halves of the guide member are swivelled away from one another, to expose the strap which is then enlarged to fit the object.
Other published matter dealing with the subject matter of the present invention include U.S. Pat. Nos. 1.357,883; 3,146,694; 3,215,064; 3,442,732; 3,442,732; 3,447,447; 3,494,280; 3,554,844; 3,566,778; 3,636,861; 3,691,939; 3,718,526; 3,875,855; 3,916,779; 3,946,659; and 4,062,278; German Patent Application No. As 24 03 261; German Laid Open Patent Application No. 1 153 318; Great Britain Patent Specification No. 936,718; and Swiss Pat. No. 388 182.
However, the prior art dose not suggest or teach the simple structure of a binding apparatus in accordance with the present invention wherein a onee-piece guide member encloses an interior region, defines therein a guide surface, and is swivelable between first and second position, on and off a loop forming area on a bed-plate. The one-piece guide member of the present invention is structurally simple and provides full and unimpeded access to the loop of tape and operates very reliably.